lgoodson@pacbell.net Posted January 23, 2010 Share Posted January 23, 2010 For those of you that have read my posts as to the noise problem, I want to give you some resolution. I first noticed that if I replaced my steel braided pressure fuel line with a long rubber one, the noise was almost all the gone. I then had one made the correct length , about 9", and the noise came back a little but not bad so I was happy. BUT while re-reading the JTR "TPI" manual for the tenth time I noticed a small section in the fuel pump section. 2 1/2 lines to be exact. It talked about a fuel "damper or pulsator". The purpose of which is to "quiet" the noise made by the injectors due to fuel pump pulsations. Imagine that!. The LT1 fuel rail comes with a device called an "acumulator" which I believe does the same thing. One fine fellow (not on this site) told me to discard that device, everyone does he said. Imagine that!!. There must be a lot of noisy LT1's running around. I haven't reinstalled it yet, it will take some doing but I will let you know. I don't know about you but my car, at 70 mph, has a lot of noise in it, Can't hardly hear the radio so Injector noise and fuel pump noise can't be allowed. I have told you all that I switched to a BMW fuel pump which is soooo much quieter. I am also gong to insulate the doors and floor boards with a product called DynaMat so that should make a big difference. By the way, the BMW fuel pump I installed appeared to be a OEM pump so I bought a nother one that looked newer, They both work but the OEM one is quieter but it is old so I carry a spare. I should maybe have it installed and wired seperatly. Just in case. The one I have in it now, you can barely hear before start up and not at all after start. AS I said, this kind of noise can't be allowed. Larry 1 Quote Link to comment Share on other sites More sharing options...
deja Posted January 23, 2010 Share Posted January 23, 2010 You got nailed with that 93 engine again. Hope that fixes your noise but GM put it in there for a reason. It might be your fuel pump thats the real problem. The 93 Fuel Rails had the crossover located at the rear of the rails with an integral accumulator, and had no crossover up front. The 94+ fuel rails had the crossover at the front of the fuel rails which subsequently caused an intake manifold design change allowing a recess for the front located crossover, and the accumulator was deleted." For those of you that have read my posts as to the noise problem, I want to give you some resolution.I first noticed that if I replaced my steel braided pressure fuel line with a long rubber one, the noise was almost all the gone. I then had one made the correct length , about 9", and the noise came back a little but not bad so I was happy. BUT while re-reading the JTR "TPI" manual for the tenth time I noticed a small section in the fuel pump section. 2 1/2 lines to be exact. It talked about a fuel "damper or pulsator". The purpose of which is to "quiet" the noise made by the injectors due to fuel pump pulsations. Imagine that!. The LT1 fuel rail comes with a device called an "acumulator" which I believe does the same thing. One fine fellow (not on this site) told me to discard that device, everyone does he said. Imagine that!!. There must be a lot of noisy LT1's running around. I haven't reinstalled it yet, it will take some doing but I will let you know. I don't know about you but my car, at 70 mph, has a lot of noise in it, Can't hardly hear the radio so Injector noise and fuel pump noise can't be allowed. I have told you all that I switched to a BMW fuel pump which is soooo much quieter. I am also gong to insulate the doors and floor boards with a product called DynaMat so that should make a big difference. By the way, the BMW fuel pump I installed appeared to be a OEM pump so I bought a nother one that looked newer, They both work but the OEM one is quieter but it is old so I carry a spare. I should maybe have it installed and wired seperatly. Just in case. The one I have in it now, you can barely hear before start up and not at all after start. AS I said, this kind of noise can't be allowed. Larry 1 Quote Link to comment Share on other sites More sharing options...
lgoodson@pacbell.net Posted January 25, 2010 Author Share Posted January 25, 2010 I changed the fuel pump 3 times and the noise persisted. Don't think it is the pump. Adding the rubber fuel hose made a big difference but I will re install the cumulator and see what happens. Quote Link to comment Share on other sites More sharing options...
deja Posted January 25, 2010 Share Posted January 25, 2010 Just seems like there is a reason GM put that thing on, just removing it might cause other problems. Maybe go to http://www.z28.com/forum/forum10/ and ask for opinions. Quote Link to comment Share on other sites More sharing options...
gvincent Posted January 29, 2010 Share Posted January 29, 2010 What was the part number on the BMW fuel pump and replacement pump. I have a Mallory EFI-110 pump that is noisy and then bought a Paxton pump which was built by Aeromotive and is the same as the 1000 but it was noisier than the Mallory. I was thinking of getting a Walbro 255 but your BMW pump sounds like it might be quieter. Both pumps were mounted with 4 rubber isolator 1/4-20 studs (metal stud-3/4" rubber-metal stud, so no metal to metal) but I can still hear the pump over my custom sidepipes. Bought a stereo for Xmas for the car and want to listen to some tunes. but the constant droning of the pump noise inside is too much. I will have a couple of slightly used hi performance fuel pumps for sale soon I hope! Thanks, Greg 1 Quote Link to comment Share on other sites More sharing options...
lgoodson@pacbell.net Posted January 29, 2010 Author Share Posted January 29, 2010 Greg, I just went to the local Pick Your Part and found a couple of BMW's that had the pumps in them. I pulled the one from the BMW 633 and one from a 530. The 530 looked newer so I thought I would probably use that one but as it turned out the 633 pump was a lot quieter. Here's what I think. The 633 pump looked original and the 533 pump looked replaced so I think the original equipment is maybe quieter by design than the repalacement so you might want to buy a dealer supplied pump for a 1984 BMW 633. Both pumps are rated at 50 GPH and 100 to 110 PSI. The stock LT1 is rated at 50 GPH and 90 to 100 PSI. Both pumps are much quieter than the 280ZX Turbo that I had in it which just droned on over the Magnaflow. Just pick one up at the wrecking yard and try it. Look for a large BMW. 735 or 740 or 633 or the 530, vintage 1980's because that is when they had external pumps. They are about $20 used and $100 new I think. Autozone is the place where I get this info. Really happy with mine though so far. It's just barley loud enough so I can hear it is running so that I know it is running before I start the engine and after start up, I can't hear it at all. My pump is mounted using the 280ZX rubber insulated mount. The pumps are almost the same size. Any experience with Dynamat Extreme sound proofing. I am about to start that process . I would like to be able hear the radio at 70MPH Larry Quote Link to comment Share on other sites More sharing options...
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